/*
	Copyright (C) 1996-1997  Id Software, Inc.

	This program is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; if not, write to the Free Software
	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

	See file, 'COPYING', for details.
*/

// divide.h

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <stdlib.h>

#include "QF/sys.h"

#include "bsp5.h"

/*
a surface has all of the faces that could be drawn on a given plane

the outside filling stage can remove some of them so a better bsp can be
generated
*/
surface_t   newcopy_t;
int         subdivides;


/*
===============
SubdivideFace

If the face is >256 in either texture direction, carve a valid sized
piece off and insert the remainder in the next link
===============
*/
void
SubdivideFace (face_t *f, face_t **prevptr)
{
	face_t     *front, *back, *next;
	float       mins, maxs;
	int         axis, i;
	plane_t     plane;
	texinfo_t  *tex;
	vec_t       v;

// special (non-surface cached) faces don't need subdivision
	tex = &bsp->texinfo[f->texturenum];

	if (tex->flags & TEX_SPECIAL)
		return;


	for (axis = 0; axis < 2; axis++) {
		while (1) {
			mins = 9999;
			maxs = -9999;

			for (i = 0; i < f->numpoints; i++) {
				v = DotProduct (f->pts[i], tex->vecs[axis]);
				if (v < mins)
					mins = v;
				if (v > maxs)
					maxs = v;
			}

			if (maxs - mins <= subdivide_size)
				break;

			// split it
			subdivides++;

			VectorCopy (tex->vecs[axis], plane.normal);
			v = VectorLength (plane.normal);
			VectorNormalize (plane.normal);
			plane.dist = (mins + subdivide_size - 16) / v;
			next = f->next;
			SplitFace (f, &plane, &front, &back);
			if (!front || !back)
				Sys_Error ("SubdivideFace: didn't split the polygon");
			*prevptr = back;
			back->next = front;
			front->next = next;
			f = back;
		}
	}
}

void
SubdivideFaces (surface_t *surfhead)
{
	face_t     *f, **prevptr;
	surface_t  *surf;

	qprintf ("--- SubdivideFaces ---\n");

	subdivides = 0;

	for (surf = surfhead; surf; surf = surf->next) {
		prevptr = &surf->faces;
		while (1) {
			f = *prevptr;
			if (!f)
				break;
			SubdivideFace (f, prevptr);
			f = *prevptr;
			prevptr = &f->next;
		}
	}

	qprintf ("%i faces added by subdivision\n", subdivides);

}

/*
=============================================================================
GatherNodeFaces

Frees the current node tree and returns a new chain of the surfaces that
have inside faces.
=============================================================================
*/
void
GatherNodeFaces_r (node_t *node)
{
	face_t     *next, *f;

	if (node->planenum != PLANENUM_LEAF) {
// decision node
		for (f = node->faces; f; f = next) {
			next = f->next;
			if (!f->numpoints) {		// face was removed outside
				FreeFace (f);
			} else {
				f->next = validfaces[f->planenum];
				validfaces[f->planenum] = f;
			}
		}

		GatherNodeFaces_r (node->children[0]);
		GatherNodeFaces_r (node->children[1]);

		free (node);
	} else {
// leaf node
		free (node);
	}
}

surface_t  *
GatherNodeFaces (node_t *headnode)
{
	memset (validfaces, 0, sizeof (validfaces));
	GatherNodeFaces_r (headnode);
	return BuildSurfaces ();
}

//===========================================================================

typedef struct hashvert_s {
	struct hashvert_s *next;
	vec3_t      point;
	int         num;
	int         numplanes;				// for corner determination
	int         planenums[2];
	int         numedges;
} hashvert_t;

#define	POINT_EPSILON	0.01

int         c_cornerverts;

hashvert_t  hvertex[MAX_MAP_VERTS];
hashvert_t *hvert_p;

face_t     *edgefaces[MAX_MAP_EDGES][2];
int         firstmodeledge = 1;
int         firstmodelface;

//============================================================================

#define	NUM_HASH	4096

hashvert_t *hashverts[NUM_HASH];

static vec3_t hash_min, hash_scale;

static void
InitHash (void)
{
	int         i;
	int         newsize[2];
	vec3_t      size;
	vec_t       scale, volume;

	memset (hashverts, 0, sizeof (hashverts));

	for (i = 0; i < 3; i++) {
		hash_min[i] = -8000;
		size[i] = 16000;
	}

	volume = size[0] * size[1];

	scale = sqrt (volume / NUM_HASH);

	newsize[0] = size[0] / scale;
	newsize[1] = size[1] / scale;

	hash_scale[0] = newsize[0] / size[0];
	hash_scale[1] = newsize[1] / size[1];
	hash_scale[2] = newsize[1];

	hvert_p = hvertex;
}

static unsigned
HashVec (vec3_t vec)
{
	unsigned    h;

	h = hash_scale[0] * (vec[0] - hash_min[0]) * hash_scale[2]
		+ hash_scale[1] * (vec[1] - hash_min[1]);
	if (h >= NUM_HASH)
		return NUM_HASH - 1;
	return h;
}

int
GetVertex (vec3_t in, int planenum)
{
	hashvert_t *hv;
	int         h, i;
	vec3_t      vert;

	for (i = 0; i < 3; i++) {
		if (fabs (in[i] - (int) (in[i] + 0.5)) < 0.001)
			vert[i] = (int) (in[i] + 0.5);
		else
			vert[i] = in[i];
	}

	h = HashVec (vert);

	for (hv = hashverts[h]; hv; hv = hv->next) {
		if (fabs (hv->point[0] - vert[0]) < POINT_EPSILON
			&& fabs (hv->point[1] - vert[1]) < POINT_EPSILON
			&& fabs (hv->point[2] - vert[2]) < POINT_EPSILON) {
			hv->numedges++;
			if (hv->numplanes == 3)
				return hv->num;			// already known to be a corner
			for (i = 0; i < hv->numplanes; i++)
				if (hv->planenums[i] == planenum)
					return hv->num;		// already know this plane
			if (hv->numplanes == 2)
				c_cornerverts++;
			else
				hv->planenums[hv->numplanes] = planenum;
			hv->numplanes++;
			return hv->num;
		}
	}

	hv = hvert_p;
	hv->numedges = 1;
	hv->numplanes = 1;
	hv->planenums[0] = planenum;
	hv->next = hashverts[h];
	hashverts[h] = hv;
	VectorCopy (vert, hv->point);
	hv->num = bsp->numvertexes;
	if (hv->num == MAX_MAP_VERTS)
		Sys_Error ("GetVertex: MAX_MAP_VERTS");
	hvert_p++;

// emit a vertex
	if (bsp->numvertexes == MAX_MAP_VERTS)
		Sys_Error ("numvertexes == MAX_MAP_VERTS");

	bsp->vertexes[bsp->numvertexes].point[0] = vert[0];
	bsp->vertexes[bsp->numvertexes].point[1] = vert[1];
	bsp->vertexes[bsp->numvertexes].point[2] = vert[2];
	bsp->numvertexes++;

	return hv->num;
}

//===========================================================================

int         c_tryedges;

/*
==================
GetEdge

Don't allow four way edges
==================
*/
int
GetEdge (vec3_t p1, vec3_t p2, face_t *f)
{
	dedge_t    *edge;
	int         v1, v2, i;

	if (!f->contents[0])
		Sys_Error ("GetEdge: 0 contents");

	c_tryedges++;
	v1 = GetVertex (p1, f->planenum);
	v2 = GetVertex (p2, f->planenum);
	for (i = firstmodeledge; i < bsp->numedges; i++) {
		edge = &bsp->edges[i];
		if (v1 == edge->v[1] && v2 == edge->v[0]
			&& !edgefaces[i][1]
			&& edgefaces[i][0]->contents[0] == f->contents[0]) {
			edgefaces[i][1] = f;
			return -i;
		}
	}

// emit an edge
	if (bsp->numedges == MAX_MAP_EDGES)
		Sys_Error ("numedges == MAX_MAP_EDGES");
	edge = &bsp->edges[bsp->numedges];
	bsp->numedges++;
	edge->v[0] = v1;
	edge->v[1] = v2;
	edgefaces[i][0] = f;

	return i;
}

void
FindFaceEdges (face_t *face)
{
	int         i;

	face->outputnumber = -1;
	if (face->numpoints > MAXEDGES)
		Sys_Error ("WriteFace: %i points", face->numpoints);

	for (i = 0; i < face->numpoints; i++)
		face->edges[i] = GetEdge
			(face->pts[i], face->pts[(i + 1) % face->numpoints], face);
}

/*
=============
CheckVertexes
// debugging
=============
*/
void
CheckVertexes (void)
{
	hashvert_t *hv;
	int         cb, c0, c1, c2, c3;

	cb = c0 = c1 = c2 = c3 = 0;
	for (hv = hvertex; hv != hvert_p; hv++) {
		if (hv->numedges < 0 || hv->numedges & 1)
			cb++;
		else if (!hv->numedges)
			c0++;
		else if (hv->numedges == 2)
			c1++;
		else if (hv->numedges == 4)
			c2++;
		else
			c3++;
	}

	qprintf ("%5i bad edge points\n", cb);
	qprintf ("%5i 0 edge points\n", c0);
	qprintf ("%5i 2 edge points\n", c1);
	qprintf ("%5i 4 edge points\n", c2);
	qprintf ("%5i 6+ edge points\n", c3);
}

/*
=============
CheckEdges
// debugging
=============
*/
void
CheckEdges (void)
{
	dedge_t    *edge;
	dvertex_t  *d1, *d2;
	face_t     *f1, *f2;
	int			c_multitexture, c_nonconvex, i;

	c_nonconvex = c_multitexture = 0;

//	CheckVertexes ();

	for (i = 1; i < bsp->numedges; i++) {
		edge = &bsp->edges[i];
		if (!edgefaces[i][1]) {
			d1 = &bsp->vertexes[edge->v[0]];
			d2 = &bsp->vertexes[edge->v[1]];
			qprintf ("unshared edge at: (%8.2f, %8.2f, %8.2f) (%8.2f, %8.2f, "
					 "%8.2f)\n", d1->point[0], d1->point[1], d1->point[2],
					 d2->point[0], d2->point[1], d2->point[2]);
		} else {
			f1 = edgefaces[i][0];
			f2 = edgefaces[i][1];
			if (f1->planeside != f2->planeside)
				continue;
			if (f1->planenum != f2->planenum)
				continue;

			// on the same plane, might be discardable
			if (f1->texturenum == f2->texturenum) {
				hvertex[edge->v[0]].numedges -= 2;
				hvertex[edge->v[1]].numedges -= 2;
				c_nonconvex++;
			} else
				c_multitexture++;
		}
	}

//	qprintf ("%5i edges\n", i);
//	qprintf ("%5i c_nonconvex\n", c_nonconvex);
//	qprintf ("%5i c_multitexture\n", c_multitexture);

//	CheckVertexes ();
}

void
MakeFaceEdges_r (node_t *node)
{
	face_t     *f;

	if (node->planenum == PLANENUM_LEAF)
		return;

	for (f = node->faces; f; f = f->next)
		FindFaceEdges (f);

	MakeFaceEdges_r (node->children[0]);
	MakeFaceEdges_r (node->children[1]);
}

void
MakeFaceEdges (node_t *headnode)
{
	qprintf ("----- MakeFaceEdges -----\n");

	InitHash ();
	c_tryedges = 0;
	c_cornerverts = 0;

	MakeFaceEdges_r (headnode);

//	CheckEdges ();

	GrowNodeRegions (headnode);

	firstmodeledge = bsp->numedges;
	firstmodelface = bsp->numfaces;
}